How to build a query in DAX using X++ code

The following code demonstrates how a query is built from scratch in X++. This query returns all sales orders, from the SalesTable, for customer '4008', sorted by the SalesId.

Query query;
QueryRun queryRun;
QueryBuildDataSource qbds;
QueryBuildRange qbr;
SalesTable SalesTable;
;

query = new Query();

//this line attaches a table to the qbds data source object
qbds = query.addDataSource(TableNum (SalesTable));

//this line attaches a range to the 'SalesTable' //data source, the range is the CustAccount
qbr = qbds.addRange(FieldNum (SalesTable,CustAccount));

// The range is set to '2001'
qbr.value ('2001');

// The query will sort by sales id
qbds.addSortField (FieldNum(SalesTable,SalesId));

// The queryRun object is instantiated using the query
queryRun = new QueryRun(query);

// The queryRun object loops through all records returned
while (queryRun.next())
{

// The current record is assigned to the salesTable variable
SalesTable = queryRun.get(tableNum(SalesTable));

print SalesTable.SalesId;
}